Question

  

Answer 1

a:ĐKXĐ: \(\dfrac{x}{2}-\dfrac{\Omega}{6}\ne\dfrac{\Omega}{2}+k\Omega\)

=>\(\dfrac{x}{2}\ne\dfrac{2}{3}\Omega+k\Omega\)

=>\(x\ne\dfrac{4}{3}\Omega+k2\Omega\)

b: ĐKXĐ: \(2x-\dfrac{\Omega}{4}\ne k\Omega\)

=>\(2x\ne\dfrac{\Omega}{4}+k\Omega\)

=>\(x\ne\dfrac{\Omega}{8}+\dfrac{k\Omega}{2}\)

c: ĐKXĐ: \(sin3x\ne0\)

=>\(3x\ne k\Omega\)

=>\(x\ne\dfrac{k\Omega}{3}\)

 

d: \(0< =cos^2x< =1\)

=>\(0>=-cos^2x>=-1\)

=>\(3>=-cos^2x+3>=-1+3=2\)

vậy: \(-cos^2x+3\ne0\forall x\)

vậy: TXĐ là D=R

e: ĐKXĐ: \(3\cdot sinx-\Omega\ne0\)

=>\(3\cdot sinx\ne\Omega\)

=>\(sinx\ne\dfrac{\Omega}{3}\)(luôn đúng)

Vậy: TXĐ là D=R